Feasibility study of producing multi-metal parts by Fused Filament Fabrication (FFF) technique

Additive manufacturing, or more commonly 3D printing, has been recently established as one of the most advanced technologies for fabricating multi-material parts. In this work, the possibility of manufacturing multi-metal parts by material extrusion process was studied for the first time. Three types of samples, named mixed, coupled and graded, resulting from deposition of two ferrous alloys: high carbon iron and stainless steel 316 L filaments, were successfully printed. After de-binding with different heating rates, they were isothermally sintered in the range of 1310−1400 °C for various holding times in argon atmosphere. Finally, some properties of the final parts, such as relative density, shrinkage, microstructural evolution, and hardness were analyzed. In conclusion, the relative density was measured up to 92 %, and the shrinkage recorded for the samples ranged between 10 % and 40 %. Based on the performed analyses, a relatively homogeneous microstructure was observed in the mixed sample, which indicates that the affordable metal extrusion technique could replace the conventional methods for metallic alloying.